Drum lifters

ABSTRACT

A drum-lifter to enable a fork-lift truck or the like to lift drums of thermoplastics material and having barrelled lower portions. A drum-lifter has two relatively moveable parts, namely a first, drum-supporting part and a second part for attaching to lifting means. When the lifter is in an unloaded relative disposition the drum-supporting part may be placed against the lower, barrelled portion of a drum to provide support about a portion of the periphery of the drum. If the second part is then lifted the first part starts to take the weight of the drum and the two parts move against a resilient bias to a loaded relative disposition. The relative movement of the two parts causes a drum-embracing member to move into a position in which it extends the support of the first part round a further portion of the periphery of the drum.

[22] Filed:

[ 51 Dec. 30, 1975 [54] DRUM LIFTERS [75] Inventors: Vernon John Ryden, Ringwood;

Robert Lawford Oakley, Christchurch, both of England [73] Assignee: St. Clare Engineering Limited,

Hampshire, England May 13, 1974 [21] Appl. No.: 469,361

[30] Foreign Application Priority Data May 11, 1973 United Kingdom 22652/73 [52] US. Cl 294/103; 214/654; 294/87 R; 294/88; 294/110 R [51] Int. Cl. B66F 9/18 [58] Field of Search 294/66 R, 86 R, 87 R, 88, 294/103, 110 R; 214/147 G, 651, 652, 653,

3,141,375 7/1964 Randall 214/653 UX 3,363,791 1/1968 Hansen 214/654 3,472,401 10/1969 Scaperotto 294/86 R X Primary ExaminerRichard A. Schacher Assistant ExaminerJohnny D. Cherry Attorney, Agent, or Firm--Stewart and Kolasch, Ltd.

' [57] ABSTRACT A drum-lifter to enable a fork-lift truck or the like to lift drums of thermoplastics material and having barrelled lower portions.

A drum-lifter has two relatively moveable parts, namely a first, drum-supporting part and a second part for attaching to lifting means. When the lifter is in an unloaded relative disposition the drum-supporting part may be placed against the lower, barrelled portion of a drum to provide support about a portion of the periphery of the drum. If the second part is then lifted the first part starts to take the weight of the drum and the two parts move against a resilient bias to a loaded relative disposition. The relative movement of the two parts causes a drum-embracing member to move into a position in which it extends the support of the first part round a further portion of the periphery of the drum.

14 Claims, 6 Drawing Figures US. Patent Dec. 30, 1975 Sheet 1 of5 3,929,368

Nu m g SJ mt RN 3 W R) 1. 1- .:u RA N 3 w x I v: i 1 f c M1 6 N8 MS J 3 m a m C N\ ilk US. Patent Dec. 30, 1975 Sheet2of5 3,929,368

F IG. 3.

US. Patent Dec. 30, 1975 Sheet 4 of5 3,929,368

FIG. 4.

US. Patent Dec. 30, 1975 Sheet 5 of5 3,929,368

DRUM LIFTERS The present invention relates to drum-lifters, that is apparatus on or for attachment to a fork-lift truck enabling the fork-lift truck to lift drums such as 120 and 210 liter drums.

Hitherto large drums have usually been of steel and satisfactory drum-lifters of the parrots beak type such as that known as the Grab-o-matic were evolved to handle them. British Patent Specifications Nos.

"893,998 and 914,374 describe the operation of such lifters.

Recently, drums of thermoplastics material have come into use and attempts to provide drum-lifters for handling them have not been entirely successful.

The thermoplastics drums (usually of polythene) are softer than conventional metal drums (particularly in hot weather) and they do not have a rim suitable for lifting by a conventional parrots-beak type lifter. However thermoplastics drums are of a somewhat barrelled shape and one proposal has been to provide a drum lifter in the form of a horizontal two-pronged or threepronged fork. The gap between the prongs is made less than the maximum diameter of the drum and slightly more than the minimum diameter at the base of the drum. Thus the prongs can be thrust on either side of a drum at the base and thereafter the drum can be lifted by operation of the fork-lift.

Because of the insecure mounting of the drum on the prongs of the lifter, accidents have occurred and drums have toppled from the lifter. One reason for this is that the drums tend, particularly in hot weather, to deform and become oval in cross-section. The oval section drum can then slide between the prongs and either the drum is not lifted at all or else it falls off the fork-lift truck shortly after being lifted. There have also been problems with drums sliding part of the way between the prongs and becoming wedged. There is therefore a need for a drum-lifter which is capable of securely lifting drums of thermoplastics material and barrelled lower extremities. Such a drum-lifter should be as simple to operate as a drum-lifter for conventional drums and should preferably enable drums to be closely stacked in a confined space such as the interior of a cargo container.

The present invention provides a drum-lifter suitable for lifting drums of thermoplastics material and barrelled lower portions, comprising a first part adapted to support a drum and a second part for attaching to a lifting means the first and second parts being moveable between a first relative disposition when unloaded and a second relative disposition when loaded and being resiliently biased into the first disposition wherein the first part includes a support member for fitting against the lower portion of a barrelled drum, a drum-embracing member movable relative to the support member from an inoperative position to an operative position in which it embraces the lower portion of the drum to extend the support thereof, and the drum-lifter includes actuation means responsive to the relative movement between the first and the second part when going from the first, unloaded disposition to the second, loaded disposition to move the drum-embracing member to its operative position.

Preferably support is extended around 270 of the lower portion of the drum when the drum-lifter is in the loaded disposition.

displacement towards the drum during loading to press between the drum-embracing edge and the support member.

The actuation meansmay be hydraulic or it may comprise a mechanical linkage between the first part and the second part of the drum lifter.

Embodiments of the present invention will be described in detail by way of example with reference to the drawings in which:

FIG. 1 is an elevation of a row of drums;

FIG. 2 is a plan view of a portion of a first drum-lifter,

FIGS. 3 and 4 are side views of the drum-lifter of FIG. 2 and a drum respectively in an unloaded configuration and in a loaded configuration,

FIG. 5 is a plan view of one half of a second drumlifter, and 3 FIG. 6 is a side view of the drum lifter of FIG. 5.

In FIG. 1 there is a row of adjacent drums 10. The drums 10 are closely packed as they would be for transportation or in a typical storage depot. They are of circular cross-section and have bases 11 of smaller diameter than the middle portion of their bodies. There is a barrelled taper 12 towards the base 11 of each drum 10. The drums 10 do not have an upper rim like conventional metal drums but are equipped with moulded hand grips 13. Between adjacent tapered portions 12 there are gaps 15 into which the prongs of a fork-lifting device can be inserted for mechanically handling the drums 10.

FIG. 2 is a plan view of a base part 38 of a drum-lifter adapted to support the drums 10. It has two semi-circular supports 21 and 22 enclosing respective arcuate drum-embracing members 23 and 24. When the drumembracing members are retracted, the two semi-circular supports present three prongs 31, 32, 33 to a row of drums. These prongs are inserted into gaps 15 and the semi-circular supports 21 and 22 are fitted against the lower, barrelled portions 12 of a pair of adjacent drums 10. In operation the arcuate drum-embracing members 23 and 24 slide out of their respective positions into positions around the drums 10 to embrace the drums and provide support around 270 of the barrelled lower portions of the drums. In many applications it may not be necessary to slide the drum-embracing members 23 and 24 so far as- 270 around to drums 10 to provide enough support to prevent the drums from deforming.

However, a drum-lifter which does extend support around 270 of the drums should be reliable in almost all applications.

The means for extending the arcuate drum-embracing members 23 and 24 includes a hydraulically operated piston 34 which swings a lever 35 about a pivot 36. The end of the lever away from the piston is connected to two cables 25 and 26 which are attached to the respective drum-embracing members 23 and 24 at respective lugs 27 and 28. Each of the cables 25 and 26 The cables and 26 are guided around pulley wheels 29 so that an anti-clockwise rotation of the lever 35 extends the drum-embracing members 23 and 24 and a clockwise rotation retracts them. An arcuate guide 30 is provided to ensure that the cables 25 and 26 have to follow a path of the same length in all positions of the lever and that they therefore remain taut. Rollers 37 are provided to help guide the drum-embracing members 23 and 24.

Rising from the base part 38 are two posts 41 and 42, better seen in FIGS. 3 and 4. These posts are connected by a parallelogram linkage to corresponding posts 51 and 52 (the part 52 is not shown) of a connection part 58 of the drum-lifter which is adapted to fit over the prongs of an ordinary fork-lift truck. Near the top of the posts 41 and 42 there is hinged a steadying loop 43 which comprises a rigid loop of rod. It is connected to the post 51 by a linkage 44 arranged so that when the post 51 moves upwards with respect to the post 41 the steadying loop 43 is caused to swing downwards to encircle a drum and prevent it from toppling while being transported by the drum-lifter.

On the post 51 there is a hydraulic cylinder 53 which is connected to the cylinder of the piston 34. There is also a spring loaded piston 55 arranged to bias the part onto the base part 38.

In FIG. 3 the drum-lifter is in an unloaded position but fitted against a drum 10. As the connection part 58 of the drum-lifter is raised by a fork-lift truck the base part 38 is held down against the resilient bias of the piston 55 by the weight of the drum 10. The relative movement of the connection part 58 and the base part 38 causes hydraulicfluid to be forced out of the cylinder 53 and against the piston 34. This causes the lever 35 to rotate and extend the members 23 and 24 around the drum l0.

At the same time the linkage 44 brings the steadying loop 43 down over the drum 10. The drum-lifter is then in the position of FIG. 4. No further relative movement between the parts of the drum-lifter is possible and the drum is lifted. Depositing the drum simply requires the same procedure in the reverse order.

The drum-lifter of FIGS. 5 and 6 differs from that of FIGS. 2 to 4 in three important features. It is evident that drum-lifters having only one or two of the different features may also be constructed.

The first different feature is that each of the supports 21 and 22 extends for more than a semi-circle making the prongs 31, 32 and 33 appear knob-shaped in the plan view. The amount of extra support which may be provided in this way depends on the difference between the minimum base diameter of a drum to be lifted and the diameter at the level of support. In the figures the support extends about over 215 and the minimum diameter of a drum to be lifted must be less than 92% of the diameter at the level of support.

The second different feature is that the linkage between the pairs of posts 41 and 51, and 42 and 52 is not a parallelogram linkage. The lower link is shorter than the upper link. This has the effect of causing the upper end of the posts 41 and 51 to tilt backwardly as a drum is lifted, thereby reducing any tendency of a drum being carried to topple forwardly out of the drum-lifter. The steadying loop 43 is still necessary, however, to make quite sure that a lifted drum cannot topple.

The third different feature is the design of the arcuate drum-embracing member labelled 123. In the inoperative position it projects forwardly from the prong 31 and is curved upwardly to a forward end 122 like a tusk of an elephant (see FIG. 6). The backward end 121 of the drum-embracing member 123 is held in a mechanism for moving it into its operative position. The motion given to the backward end 121 includes twisting about a longitudinal axis tending to bring the curved end around a drum together with a forward movement, an outward movement and a downward movement. These movements have the effect of causing the drum-embracing member 123 to ride up over the prong 31 and take up a position (shown dashed) in which it extends the arc of the support 21. A similar arrangement of drum-embracing member is provided for the half of the drum-lifter not shown in FIG. 5.

The mechanism 110 includes a depression lever 100 and a rotation lever 102 connected to the post 51 and to the forward part of the drum-lifter. Relative movement between the connection part 58 and the rest of the drum-lifter causes these levers to operate the rest of the mechanism 110. The rotation lever 102 turns a square cross-section bar 112 about a transverse axis causing an L-shaped plate 114 mounted thereonzto rotate forwardly from an upstanding position to push the extension member forwards via a universal coupling 116.

The L-shaped plate 114 is mounted at one end via a hinge 115 with a longitudinal axis to ashoe 118 which is slidable along the bar 112. The shoe 118 has an upstanding projection 117 connected to the universal coupling 116 which is located near the middle angle of the L-shaped plate 114 while the mechanism is in the position shown in FIGS. 5 and 6. The other end of the plate 114 projects sideways parallel to thehorizontal bar 112. As the bar 112 is rotated by the rotation lever 102, the depression lever 100 forces the horizontal part of the L-shaped plate 1 l4 downwards causing the shoe 118 to slide outwards along the bar 112 andthe plate 114 to rotate about a longitudinal axis. The net effect is for the end 121 of the drum embracing member 123 to be moved forwards, outwards and downwards while being twisted about a longitudinal axis at the same time. Rings and. guide the extending member around the prong 31 so that it takes up the position shown by dotted lines. Guides 132 and 134 are positioned to help nudge the extension member into the operative position. 1

Resilient means 103 in FIG. 5 and 101 in FIG. 6 are provided to return the variousmemb ers of the .drumlifter back to the inoperative position when a drum is deposited and its weight taken off the drum-lifter. Typically a full drum weighs 500 lbs. so a convenient weight of drum to cause the two parts of the lifter to move relative to each other against the resilient bias is 50 lbs.

The edges of the semi-circular supports 21 and 22 and of the drum-embracing members such as 23 or 123 are chamfered to fit closely to the profile of the drums.

It is clear that there are many other variations of structure in which two parts of a drum-lifter can be arranged to move relative to each other and thereby cause drum-embracing members to move into an operative position around a drum. The actual disposition chosen for any one application will be a matter of design consideration determined largely, by the size and weight of the drum or drums to be lifted by the size of the fork-lift truck or other lifting device to which the drum-lifter is to be attached and'by the availability of suitable hydraulic or mechanical components.

A useful modification to any of the constructions described is to make the connection part 58 in two parts which are hinged together about a vertical axis. The two hinged parts are resiliently biassed to a normal position but may be rotated about the hinge against the bias. The arrangement is such that the base part 38 of the drum-lifter can turn about the hinge and align itself exactly with a drum even when a fork-lift truck carrying the drum-lifter is poorly aligned with the drum.

Apart from the advantages to be expected from having a degree of automatic alignment (such as reduction in wear and tear to the lifter and to the drums and reduction in driver frustration at having to start again from a drum approach that was only slightly crooked etc.), there is a further advantage applicable to the loading of containers. To pack a container fully a row of drums should extend all the way from one side wall to the other side wall. But this means that the edge drums are difficult, if not impossible, to get at with a fork-lift truck. However if the drumlifter can be misaligned against its resilient centring bias, then the fork-lift truck can be driven at a shallow angle towards the side wall of the container and the drum-lifter will engage the wall and turn inwardly to align itself with a drum near the edge. In other words difficult-to-get-at drums may successfully be lifted by exploiting the self-aligning feature and deliberately driving at the drum from a direction which is out of alignment.

We claim:

1. A drum-lifter suitable for lifting drums made of thermoplastics material having barrelled lower portions comprising a first part adapted to support a drum and having a support member for fitting against the lower portion of barrelled drum, a drum-embracing member movable relative to said support member from an inoperative position to an operative position, said drumembracing member being adapted to engage the lower'--'- portion of the barrelled drum which is fitted against said support member and extending around the lower portion of said fitted drum, a second part adapted to be attached to a lifting means, said first and second parts being interconnected and movable relative to eachother between a first unloaded position and a second loaded position, resilient means connected to bias said first and second parts towards said first, unloaded position, and actuation means arranged to move said drumembracing member to its operative position in response to relative movement between said first and second parts from the unloaded position towards the loaded position against said resilieint bias caused by lifting said second part with a load on said first part.

2. A drum-lifter according to claim 1 adapted in said loaded position, to extend support around at least 270 of said lower portion of said fitted drum.

3. A drum-lifter according to claim 1 wherein said drum-embracing member comprises an arcuate member mounted for circumferential movement relative to said support member between a retracted, inoperative position and an extended operative position.

4. A drum-lifter according to claim 1 wherein said drum-embracing member has a curved, drum-embracing edge which is mounted in said inoperative position to curve, tusk-like, in a substantially vertical plane and to project forwardly from one side of said support member said drum-embracing member, in said opera- 6 tive position, turning inwardly towards a drum fitted against said support member.

5. A drum-lifter according to claim 4 wherein said drumembracing edge turns inwardly to its operative position to extend in a plane which is at not more than to the horizontal.

6. A drum-lifter according to claim 4 wherein said drum-embracing edge is mounted for rearward displacement towards a drum during loading to press said drum between said drum-embracing edge and said support member.

7. A drum-lifter according to claim 6 wherein said curved drum-embracing edge is mounted on the end of a longitudinally extending arm which is mounted free to rotate about its longitudinal axis and to move in the longitudinal direction and is connected to said actuation means at its rear end portion.

8. A drum-lifter according to claim 7 wherein the forward end of the arm is pivoted about a vertical axis and said rear end is moved outwardly during loading to move said drum-embracing edge inwardly and rearwardly to press against a drum.

9. A drum-lifter according to claim 1 wherein said actuation means comprises a driving hydraulic cylinder and piston responsive to said relative movement and a driven hydraulic cylinder and piston hydraulically connected to said driving hydraulic cylinder and piston.

10. A drum-lifter according to claim 1 wherein said actuation means comprises a'mechanical linkage between said first part and said second part of said drumlifter.

11. A drum-lifter according to claim 1 wherein only a portion of a drum weight is needed to move said drum-embracing member into said operative position and the remaining portion of the drum weight serves to tighten the grip of said drum-embracing member and said support member on a drum.

12. A drum-lifter according to claim 11 wherein a weight of about pounds is needed to move said drum-embracing member into said operative position.

13. A drum-lifter according to claim 1 including two of said drum-embracing members mounted one on each side of said support member.

14. A drum-lifter, provided with a lifting means, and suitable for lifting drums having a barrel shape and made of thermoplastic material which comprises a base element for supporting the drums, said base element provided at one side with two semi-circular support elements, an arcuate drum-embracing member housed by each of said semi-circular support elements, actuating means operatively associated with said drumembracing members for extending and retracting said members from the semi-circular support members, said drum-embracing members, in their extended position, being adapted to engage and extend around the lower portion of the drums, a connecting element connected to the lifting means, means for connecting the base element with the connecting element, said base ele ment and said connecting element being movable, relative to each other between a first unloaded position and a second loaded position, and resilient means connected to bias said base element and said connecting element toward said first, unloaded position, said actuating means moving said drum-embracing members to their extended, operative position in response to relative movements between said base element and said connecting element from the unloaded position towards the loaded position against said resilient bias caused by lifting said connecting element with a load on said base element. 

1. A drum-lifter suitable for lifting drums made of thermoplastics material having barrelled lower portions comprising a first part adapted to support a drum and having a support member for fitting against the lower portion of barrelled drum, a drum-embracing member movable relative to said support member from an inoperative position to an operative position, said drum-embracing member being adapted to engage the lower portion of the barrelled drum which is fitted against said support member and extending around the lower portion of said fitted drum, a second part adapted to be attached to a lifting means, said first and second parts being interconnected and movable relative to each other between a first unloaded position and a second loaded position, resilient means connected to bias said first and second parts towards said first, unloaded position, and actuation means arranged to move said drumembracing member to its operative position in response to relative movement between said first and second parts from the unloaded position towards the loaded position against said resilieint bias caused by lifting said second part with a load on said first part.
 2. A drum-lifter according to claim 1 adapted in said loaded position, to extend support around at least 270* of said lower portion of said fitted drum.
 3. A drum-lifter according to claim 1 wherein said drum-embracing member comprises an arcuate member mounted for circumferential movement relative to said support member between a retracted, inoperative position and an extended operative position.
 4. A drum-lifter according to claim 1 wherein said drum-embracing member has a curved, drum-embracing edge which is mounted in said inoperative position to curve, tusk-like, in a substantially vertical plane and to project forwardly from one side of said support member said drum-embracing member, in said operative position, turning inwardly towards a drum fitted against said support member.
 5. A drum-lifter according to claim 4 wherein said drum-embracing edge turns inwardly to its operative position to extend in a plane which is at not more than 25* to the horizontal.
 6. A drum-lifter according to claim 4 wherein said drum-embracing edge is mounted for rearward displacement towards a drum during loading to press said drum between said drum-embracing edge and said support member.
 7. A drum-lifter according to claim 6 wherein said curved drum-embracing edge is mounted on the end of a longitudinally extending arm which is mounted free to rotate about its longitudinal axis and to move in the longitudinal direction and is connected to said actuation means at its rear end portion.
 8. A drum-lifter according to claim 7 wherein the forward end of the arm is pivoted about a vertical axis and said rear end is moved outwardly during loading to move said drum-embracing edge inwardly and rearwardly to press against a drum.
 9. A drum-lifter according to claim 1 wherein said actuation means comprises a driving hydraulic cylinder and piston responsive to said relative movement and a driven hydraulic cylinder and piston hydraulically connected to said driving hydraulic cylinder and piston.
 10. A drum-lifter according to claim 1 wherein said actuation means comprises a mechanical linkage between said first part and said second part of said drum-lifter.
 11. A drum-lifter according to claim 1 wherein only a portion of a drum weight is needed to move said drum-embracing member into said operative position and the remaining portion of the drum weight serves to tighten the grip of said drum-embracing member and said support member on a drum.
 12. A drum-lifter according to claim 11 wherein a weight of about 50 pounds is needed to move said drum-embracing member into said operative position.
 13. A drum-lifter according to claim 1 including two of said drum-embracing members mounted one on each side of said support member.
 14. A drum-lifter, provided with a lifting means, and suitable for lifting drums having a barrel shape and made of thermoplastic material which comprises a base element for supporting the drums, said base element provided at one side with two semi-circular support elements, an arcuate drum-embracing member housed by each of said semi-circular support elements, actuating means operatively associated with said drum-embracing members for extending and retracting said members from the semi-circular support members, said drum-embracing members, in their extended position, being adapted to engage and extend around the lower portion of the drums, a connecting element connected to the lifting means, means for connecting the base element with the connecting element, said base element and said connecting element being movable, relative to each other between a first unloaded position and a second loaded position, and resilient means connected to bias said base element and said connecting element toward said first, unloaded position, said actuating means moving said drum-embracing members to their extended, operative position in response to relative movements between said base element and said connecting element from the unloaded position towards the loaded position against said resilient bias caused by lifting said connecting element with a load on said base element. 